Strength and power measured at 1 time point are more predictive of mobility decline in older adults than 3-year changes, say authors of an article published in Journal of Gerontology, Series A. Low strength and power are particularly powerful risk factors in men, they add.

This longitudinal analysis of 934 adults aged ≥65 years, who were enrolled in the Invecchiare in Chianti study, measured grip strength, knee extension strength, and lower extremity power at baseline and 3 years postenrollment. Mobility function (gait speed and self-reported mobility disability) was measured at 3 and 6 years postenrollment. Classification and regression tree analysis was used to predict mobility decline from years 3 to 6.

Men with knee extension strength <19.2 kg and grip strength <39.0 kg had clinically meaningful declines in gait speed of .24 meters per second (m/s). Furthermore, men with power <105 W were nearly 9 times more likely to develop incident mobility disability (likelihood ratio = 8.68). Among women, knee extension strength <18.0 kg was associated with a minimal gait speed decline of 0.06 m/s. Women with leg power <64 W were 3 times more likely to develop incident mobility disability (likelihood ratio = 3.01). Three-year changes in strength and power did not predict mobility decline in either sex.

APTA member Gregory E. Hicks, PT, PhD, was the lead author on the study.